As compared with traditional wire-based networks, optical fiber communication networks are capable of transmitting significantly more information at significantly higher speeds. Optical fibers, therefore, are being increasingly employed in communication networks.
To expand total transmission throughput, optical-fiber network providers are attempting to place ever more optical fibers in ever-smaller spaces. Packing fibers into tight spaces, however, can cause undesirable attenuation. Indeed, there is an inherent trade-off between increased fiber density and signal attenuation.
Many optical-fiber cables designed for installation in microducts (e.g., via blowing) achieve high fiber counts and relatively small cable diameters. For example, commonly assigned U.S. Pat. No. 6,912,347 (Rossi et al.), which is hereby incorporated by reference in its entirety, achieves optical-fiber cables with high fiber counts and small cable diameters.
Such optical-fiber cables can achieve higher fiber densities, but the constituent buffer tubes have unsatisfactory mid-span storage performance as positioned in pedestals, cabinets, or other optical-fiber enclosures. By way of illustration, after installation in a microduct, an optical-fiber cable typically experiences temperature cycles during use. These temperature cycles can lead to signal attenuation. Thus, a fiber-optic cable that is less susceptible to attenuation is more suitable for such installations (e.g., installations requiring mid-span storage).
Similarly, U.S. Patent Publication No. 2007/0274647 A1 (Pizzorno et al.), now U.S. Pat. No. 7,373,057, each of which is hereby incorporated by reference in its entirety, discloses an optical-fiber cable structure suitable for microduct installation. This publication requires the use of bend-insensitive fibers to reduce cable size.
Despite efforts to achieve high-fiber-density optical-fiber cables that can be installed in microducts, a need continues to exist for improved optical-fiber cables and buffer tubes that not only possess desirable optical fiber densities, but also are capable of satisfactory mid-span storage.